Circuit for heating the filaments of audions



CIRCUIT FOR HEATING THE FILAMENTS OF AUDION S Filed Oct. 4:. 1920 y My.

" Patented 12, 1924s units!) STATES DAVID G. BLAT'I NIER, OF BOGOTA, NEWJERSEY, ASSIGNOR T WESTERN ELECTBIQ 1,483,273 PATENT OFFlCE.

COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

I CIRCUIT FOR HEATING THE FILAMENTS 0F AUDIONS.

Application filed October 4, 1920. Serial No. 414,449.

To allw-homz'tmg concm: 7

Be it known that I, DAVID G. BLA'I'INER, a citizen of the United States,residing at"- Bogota, in the countyof Bergen, State'of New Jersey, haveinvented certain new and cathode of an electron discharge device withoutintroducing into the circuit fluctuations of a frequency correspondingto the cathode heating frequency. According to that arrangement, thegrid and anode electrodes are connected to the midpoint of the secondarywinding oh the transformer which connects the heating source tothecathode. In applying this arrangement to a plurality of electrondischarge devices, a separate transformer winding having a midpointconnection is provided for the cathode of each tube according to thedisclosure in the patent. According to the present invention, thefluctuations of the cathode -heating freuency are suppressed withoutnecessitating t e use of a transformer, and consequently withoutrequiring that a connection be made to the midpoint of a transformerwinding. Furtherniorainstead of employing a com pensating circuit whichis individual to each cathode, as in the patent, the present inventionprovides a compensatin circuit which is common to a plurality o' vacuumtubes. In case it is desired to apply the arran ement to a push-pulltube circuit wherem two tubes are connected in opposition in the samecircuit, an impedance may be connected in shunt to the. two cathodes,

taps being taken from the-midpoint of this impedance to theanode andcontrol elec-.- trodes. When'the connections are made in this way theaverage difierence of potential at "any instant between differentportions of the cathodes and the grids and anodes, due

,to the heating currents, will be zero an% 59 "consequently noobjectionable tone or noise is introduced into the circuit due to theuse of alternating currents for heating the cathodes This will bedescribed in connection with the drawings, which show diagrammatically arepeatingcircuit embodying one form of the invention.

Referring'in, detail to the drawings, there is connected between theincoming-line 1 and the outgoing line 2, by means of transformers 3 and4, a push-pull vacuum tube device comprising the electron dischargetubes 5 and 6, which are adapted to repeat and amplify the alternatingcurrents applied to line 1. If desired, a potentiometer 7 may beemployed in the line 1. The vacuum tube 5 comprises a cathode 8, ananode 9, and a control electrode 10, and the vacuum tube 6 containssimilar electrodes identified by corresponding numbers primed. Thefilamentary cathodes 8 and 8 are adapted tobe heated by a source 11 ofdirect current when the switch 12 is in the position shown. Preferablythe cathodes are heated by a source 13 of alternating currents which isconnected, when the switch 12 is in its alternate position, to theimpedance 14, preferably or conveniently a resistance, in shunt to whichare connected the filaments 8 and 8. The midpoint of the impedance 14 isgrounded at 15 in order to complete a circuit through gmund 16, battery17, and the halvesrof thesecondary winding of transformer 3 to the twogrids 10 and 10. The anode circuits are completed through the halves ofthe primary windings of the transformer sistance 19 without interferingwith the compensating connection. If desired the resistance 19 may beconnected between transformer 20 and source 13 instead of in thesecondary circuit of this transformer as shown.

. In wave repeating and amplifying systems where high amplification issecured, it,

is' desirable to ground the cathode of the repeater in {order to reducethe capacity to ground of the connecting wires and therebypreventsinging of the repeater. The presentinvegition provides asymmetrical path to ground for each repeater whereby the groundconnection does not interfere with l the circuit employed to suppressthe fluctuations which-tend to be present due to the use of alternatingcurrents for heating the cathodes.

. other tube.

If desired, the compensating grounded connection may be used inconnection with a plurality of sets of push-pull repeaters such as shownconnected in tandem, 1. e., the out-going line 2 may include one. ormore vacuum tube repeaters such as shown.

Each of the tubes of the push-pull amplifier substantially prevents thealternations of heating current in the cathode of the other tube fromcausing current variations in the output circuit of the amplifier,whether or not the connections of the and anodes of the tubes to thecathodes are madein such manner that the avera'ge difference ofpotential at any instant between different portions of the cathode andthe grid and anode of either tube due to the heating currents, is zero;for at any instant when the heating current would increase the averagedifi'erence of potential between the cathode and the grid or the anodeof one of the tubes, the heating current would increase the averagedifierence of potential between the cathode and the grid or the anode ofthe However, the connection ofthe grids and the anodes to the midpointof the impedance 14 isL-desirable for overcoming any lack ofcompensation due to lack of symmetry or balance between the two halvesof the push-pull circuit.

Although the invention is set forth particularly with reference to apush-pull amplifier employing two tubes, it is to be understood that asingle tube may be used instead, after the fashion disclosed, forinstance, in the patent to E. H. Colpitts, No. 1,128,292, February 16,1915, entitled Electrical wave amplifier.

What is claimed'is: i

1. In a wave repeating and amplifying system, the combination ofelectron discharge devices each having a cathode and an anode connectedin opposition, a source of alternating currents for heating saidcathodes, and a compensating circuit common to said cathodes, forpreventing the alternation in the cathode heating currents from causingcurrent variations in the output circuits of said devices.

2. A push-pull vacuum tube circuit comprising electron discharge devicesconnected in opposition and having a cathode and an anode a source ofalternating currents for heating said cathodes, an impedance in shunt tosaid cathodes, a connection from an inter mediate point of saidimpedance to said anodes, and a connection from an intermediate point ofsaid impedance to ground.

3. A wave repeating and amplifying sysstem comprising an incoming line,an outgoing line, a plurality of electron discharge devices connectedtherebetween and cwhaving a cathode, an anode and a controlele'cF trode,a transformer between said discharge devices and each of said lines, asource of grids alternating currents for heating saidcathodes, animpedance in shunt to said cathodes, and a connection from anintermediate point of said impedance to each of said transformers p t 4.In a wave repeating and amplifying system, the combination of electrondischarge devices ea'ch having a cathode and an anode connecte ikinopposition, a source of alternating currntsfor heating said cathodes,and a'compensating circuit common to said cathodes, for preventing thealternations in the cathode heating currents from causing currentvariations in the output circuits of said devices, said compensatingcircuit comprising an impedance in shunt relation to each of saidcathodes.

5. An electric wave repeating apparatus comprising divided in ut anddivided output circuits, means inc uding a hot cathode for producing twoionized streams, said! streams being oppositely included in said outputcircuit, means for supplying cyclically varying heating current to saidcathode, and two electrodes for controlling said ionized streamsrespectively and oppositely connected in said input circuit."

6. A11 electric wave repeating apparatus comprising divided input anddivided output circuits, means for producing an ionized stream includedin each division of said output circuit, said means including hotcathode means, electrodes, one in each 'division of said input circuitfor controlling said ionized streams respectively, and means forsupplying cyclically varying heating current to said cathode means.

7. In an electric wave repeating appara-- tus, the combination withinput and output circuits, of two hot cathode electron dis chargerepeater elements 0 positely connected in said circuits where y one ofsaid elements is adapted to repeat certain parts, and the other, theremaining parts of said input waves, and means for supplying cyclicallyvarying heating currents to the cathodes of said repeater elements.

8. In combination, an incoming circuit, an outgoing circuit, and acircuit for transferring indications from the first to the second ofsaid circuits comprising an electric discharge device having a cathode,an anode, and an anode circuit, a source of alternating current forheating said cathode, said anode circuit being inductively coupled tosaid outgoing circuit, and a second electric discharge device having acathode heated from said source of alternating current and an anodecircuit inductive] coupled to said outgoing circuit in opposition to thefirst mentioned anode circuit.

In witness whereof, I hereunto subscribe my name this 29th day ofSeptember A.D., 1920. i

' DAVID G. BLATTNER.

DESOLAIMER 5 1,4:83,273.Dw'id G. Blatt'ner, Bogota, N.J. CIRCUIT FORHEATING THE FILAMENTS OF AUDIoNs. Patent dated February 12, 1924.Disclaimer filed June 24, 1933, by the assignee, American Telephone andTelegraph Company.

Hereby enters this disclaimer to claims 6 and 8 of said Letters Patent,to wit:

6. An electric Wave repeating apparatus comprising divided input anddivided output circuits, means for producing an ionized stream includedin each division of said output circuit, said means including hotcathode means, electrodes, one in each division .of said input circuitfor controlling said ionized streams respectively, and means forsupplying cyclically varying heating current to said cathode means.

8. In combination, an incoming circuit, an outgoing circuit, and acircuit for transferring indications from the first to the second ofsaid circuits comprising an electric discharge device having a cathode,an anode, and an anode circuit, a source of alternating current forheating said cathode, said anode circuit being inductively coupled tosaid outgoing circuit, and a second electric discharge device having acathode heated from said source of alternating current and an anodecircuit inductively coupled'to said outgoing circuit in opposition tothe first mentioned anode circuit.

0 7mm Gazette July 18,1933

